FIG. 1 is a block diagram illustrating constitution of an encoding section in an interframe block encoding and decoding apparatus in the prior art where adaptive vector quantization is used as a method of block encoding. In FIG. 1, numeral 1 designates an A/D converter, numeral 2 designates a switch for performing a time lapse of input video signal series, numeral 3 designates a raster/block scan converting circuit where digital video signal series in raster form is blocked into blocks, each of m pixels by n lines (m, n: positive integers) to form input block data, numeral 4 designates a subtractor which obtains a differential signal between the input block data and block data within the frame memory at the same position on the frame as the input block data, i.e., frame-to-frame differential block data, numeral 5 designates a mean value separation normalizing circuit which calculates a mean value and an amplitude component of the interframe differential block data in units of block and obtains a normalized input vector through the normalizing processing, numeral 6 designates a motion estimation circuit which executes motion estimation in block units using the mean value, the amplitude component and a threshold value, and outputs the motion information, numeral 7 designates a vector quantization encoder which performs vector quantization of the normalized input vector and converts it into a normalized output vector index, numeral 8 designates a transmission data buffer which performs variable word length encoding on each of the motion information, the mean value, the amplitude component and the normalized output vector index, and stores the encoded data for a definite period to transmit to a transmission line at a definite speed, numeral 9 designates an encoding control circuit which controls the input time valve and the motion estimation threshold value in response to the amount of the information stored in the transmission data buffer, numeral 10 designates a vector quantization decoder which performs decoding to reproduce the interframe differential block data from the motion information, the mean value, the amplitude component and the normalized output vector index, numeral 11 designates an adder which reproduces the input block data, numeral 12 designates a variable delay circuit, and numeral 13 designates a frame memory.
Also FIG. 2 is a block diagram illustrating the constitution of a decoding section in the interframe block encoding and decoding apparatus in the prior art where adaptive vector quantization is used in similar manner to the encoding section. In FIG. 2, numeral 14 designates a reception data buffer which receives encoded data supplied from the transmission line, stores it for a definite period while performing variable length decoding, and outputs the stored data at a speed corresponding to the decoding operation, numeral 15 designates a block/raster scan converting circuit which converts the input block data being decoded and reproduced into a raster form, and numeral 16 designates a D/A converter.
Next, the encoding and decoding operation will be described using FIGS. 1 and 2. In the decoding section, an input moving picture signal 201 is an analog signal which is raster-scanned from the left to the right and from the upper side to the lower side of the frame. The analog signal is converted into digital signal series 202 by the A/D converter 1, and then blocked into blocks of m pixels by n lines each (m, n: positive integers) in the raster/block scan converting circuit 3, thereby input block data S 203 can be obtained. Block P 204 at the same block position within the frame memory 13 is subtracted from the block data S 203, and interframe differential block data .epsilon. 205 obtained in this manner is supplied to the mean value separation normalizing circuit 5. In the mean value separation normalizing circuit 5, the interframe differential block data is converted into a k-dimensional (k=m.times.n) vector, and then the following operation is executed, thereby an intrablock mean value .mu., an amplitude component .sigma. 206 and a normalized input vector x 207 can be obtained. ##EQU1## As approximate expressions of .sigma., ##EQU2## may be used.
The mean value .mu. and the amplitude component .sigma. 206 obtained in this manner are inputted to the motion estimation circuit 6, and in comparison with a motion detection threshold value T.theta. determined by an encoding control circuit as hereinafter described, the motion estimation in block units is executed in accordance with the following conditions. As a result of the motion estimation, motion information .nu. 209 is outputted from the motion estimation circuit 6.
.vertline..mu..vertline.&lt;T.theta. and or .sigma.&lt;T.theta.: .nu.=0 (no movement)
.vertline..mu..vertline.&gt;T.theta. or .sigma.&gt;T.theta.: .nu.=1 (movement existing)
Regarding a block of .nu.=1, i.e., movement existing, the following processing is performed. The normalized input vector x 207 obtained in the mean value separation normalizing circuit 5 is vector quantized by the vector quantization encoder 7, and converted into an index i 210 of a normalized output vector y.sub.i of which distortion with respect to x becomes minimum.
The mean value .mu., the amplitude component .sigma. 206 and the normalized output vector index i 210 in the case of the movement information .nu. 209 being .nu.=1, are converted into encoded data respectively using variable word length codes or the like in the transmission buffer 8 and stored for a definite period. The transmission data buffer 8 transmits the encoded data to the transmission line at a definite speed, and also calculates the amount of stored data 211 within the buffer and supplies it to the encoding control circuit 9. The encoding control circuit 9 monitors changes of the amount of stored data 211, and performs control of ON/OFF signal 232 of the input time lapse switch and the motion detection threshold value T.theta. 208 in frame units. An example of the control method is shown in FIG. 3.
Respective data inputted to the transmission data buffer 8, i.e., the movement information .nu. 209, the mean value .mu. and the amplitude component .sigma. 206, and the normalized output vector index i 210, are decoded through the following operation in the vector quantization decoder 10 and interframe differential decoded block data .epsilon. 212 is reproduced.
at .nu.=0 then .epsilon.=0=[0, 0, . . . , 0] PA1 at .nu.=1 then .epsilon..sub.j =.sigma..multidot.y.sub.ij +.mu. (j=1, 2, . . . , k) PA1 .epsilon.=[.epsilon..sub.1, .epsilon..sub.2, . . . , .epsilon..sub.k ]
(y.sub.i : a normalized output vector corresponding to an index i)
The interframe differential decoded block data .epsilon. 212 obtained and the block data P 204 within the frame memory delayed in a prescribed period by the variable delay circuit 12 are added, thereby decoded reproduction block data S 213 is restored, and the block data at the corresponding position within the frame memory is updated. The above-mentioned process is expressed in following formulas. EQU .epsilon.=S-P EQU .epsilon.=.epsilon.+q (q: errors produced in vector quantization encoding and decoding) EQU S=P+.epsilon. EQU P=S.multidot.Z.sup.-nf (Z.sup.-nf : n-frame delay, n: a positive integer)
On the other hand, in the decoding section, the motion information .nu. 209, the mean value .mu. and the amplitude component .sigma. 206, and the normalized output vector index i 210, received in the reception data buffer 14 and subjected to variable length decoding and speed conversion, are decoded by the vector quantization decoder 10 in similar manner to the above description, and interframe differential decoded block data .epsilon. 212 is reproduced. The interframe differential decoded block data .epsilon. 212 and the block data P 204 within the frame memory outputted through the variable delay circuit 12 are added, and decoded reproduction block data S 213 is restored in similar processing to the encoding section. That is, EQU S=P+.epsilon.=S+q
is executed. The decoded reproduction block data S 213 is converted by the block/raster scan converting circuit 15 into data 214 in raster form and subjected to D/A conversion by the D/A converter 16, thereby a reproduced output moving picture signal 215 can be obtained.
Since the interframe encoding and decoding apparatus in the prior art is constituted as above described, when the motion estimation threshold value is large, errors between the amplitude value of the interframe differential decoding block at the motion information v=1 and the amplitude value at v=0 becomes large, and in the reproduced picture, deterioration in block form due to the errors becomes conspicuous at adjoining portions between the block of v=1 and the block of v=0, and the subjective quality is deteriorated, thereby the motion estimation threshold value cannot be made so large and as a result the amount of encoded information of the large motion is increased and the number of input time lapses is increased. That is, there is a problem that the number of frames of the transmitted moving pictures is decreased and instantaneity to the motion is deteriorated.
In a constitution as shown in FIGS. 4 and 5, two transmission buffers and two reception buffers are provided as a double buffer structure, and while encoded information is written in one transmission buffer by a switch 17 and a selector 18, the other transmission buffer reads the information and transmits it, so that write and read are performed simultaneously, and also in the reception buffers while one buffer performs writing by a switch 19 and a selector 20, the other buffer performs reading, so that writing and reading are performed simultaneously.
In such constitution, a delay time from writing of some picture frame up to its decoded reproduction is defined by required time of about two cycles in encoding transmission cycle of one picture frame. Consequently, when the transmission speed is slow or the amount of information produced is large, a considerable time is required for reading the transmission buffer and the delay time may become large, and since the time lapse occurs frequently and the time interval between encoded picture frames becomes large, correlation between frames becomes small and efficiency of encoding between frames is deteriorated.
Further in an interframe encoding and decoding apparatus as shown in FIGS. 6 and 7, a spatial filter 21 is used so that granular noises produced by vector quantization errors are smoothed and reduced. In FIG. 6, numeral 21 designates a spatial filter where granular noises produced by vector quantization errors are smoothed and reduced, and numeral 22 designates a selector which selects signals not passing through the spatial filter for a block discriminated as a still region by the motion estimation circuit 6.
FIGS. 8 and 9 are block diagrams illustrating constitution of the motion estimation vector quantization encoder and decoder respectively. Numeral 5 designates a mean value separation normalizing circuit which separates a mean value and amplitude of an input vector, numeral 23 designates a distortion operation circuit which calculates the distance between two vectors, numeral 24 designates a minimum distortion detecting circuit which detects a minimum distortion from the output of the distortion operation circuit 23 and outputs a strobe, numeral 25 designates a code book ROM for an output vector, numeral 26 designates an address counter which gives an address of the code book ROM 25, and numeral 27 designates an index latch where an index corresponding to the address of the code book ROM 25 is latched by detecting the minimum distortion of the output of the minimum distortion detecting circuit 24.
In FIG. 9, numeral 28 designates an amplitude multiplier which performs amplitude reproduction of a normalized output vector, and numeral 29 designates a mean value adder which adds the mean value to the amplitude reproduced output vector.
In the apparatus in such constitution, an interframe differential reproduced vector decoded in accordance with reverse processing of encoding is added to either a previous frame vector stored in the frame memory 13 or another previous frame vector passing through the spatial filter 21, and then written in the frame memory 13. Which of the previous frame vectors to be added to the differentiated reproduced vector is selected by the selector 22. The motion detecting circuit 6 discriminates whether the interframe differential input vector is a valid block (movement existing) or an invalid block, and the result is transmitted as a valid/invalid discrimination code from the motion detecting circuit 6 to the selector 22. The selector 22 selects the previous frame vector passing through the spatial filter 21 if the interframe differential input vector is a valid block, and selects the previous frame vector in the memory 13 is it is an invalid block.
Since the selector 22 selects existence/non-existence of the spatial filter 21 by using the valid/invalid discrimination code, the granular noises caused by the vector quantization encoding can be smoothed and the spatial filter 21 can act only in regions of movement to perform effective convergence in the interframe loop.
Since the apparatus in the prior art is constituted as above described, the spatial filter always acts on the previous frame signal to take the interframe differences. Consequently, in a block including sharp edges, the signal is smoothed by the spatial filter and even in a completely still state the subtractor output does not become zero, and when the threshold value of the motion estimation is low the block may be discriminated as a valid block (movement existing). As a result, there is a problem that the still edge portion does not become still in the reproduced picture, so that the vector quantization is performed again.
Another interframe encoding and decoding apparatus in the prior art is constituted as shown in FIGS. 10 and 11. In FIGS. 10 and 11, numeral 31 designates a dynamic vector quantization encoder where input block data, supplied from the raster/block scan converting circuit, are subjected to vector quantization using a dynamic code book, numeral 32 designates a dynamic vector quantization decoder where a dynamic output vector index supplied from the dynamic vector quantization encoder 31 is decoded and the output vector is reproduced, numeral 21 designates an adaptive spatial filter where smoothing processing is applied to dynamic vector quantization reproduced video signal series obtained from the dynamic vector quantization decoder 32, numeral 22 designates a selector which selects either the dynamic vector quantization reproduced video signal series or video signal series obtained by applying the smoothing processing to the signal series according to the block discrimination information, and numeral 33 designates a variable length encoder which converts the dynamic output vector index and the adaptive vector quantization encoding output data into a suitable code word.
In FIG. 11, numeral 34 designates a variable word length decoder where code series supplied from the transmission line in synchronized speed with a transmission line clock is separated into a code word, and the code word is reversely converted into encoding data in sequence, and numeral 35 designates a decoding clock generating circuit.
FIGS. 12 and 13 are block diagrams illustrating the constitution of a dynamic vector quantization encoder and decoder respectively. Numeral 23 designates a distortion operation circuit which calculates a distance between two vectors on a multi-dimensional space, i.e., distortion, numeral 24 designates a minimum distortion detecting circuit which detects the minimum distortion among distortions based on a plurality of output vectors and outputs a strobe signal, numeral 25 designates a dynamic code book, numeral 36 designates an output vector set comprising a plurality of fixed vectors (e.g., mean value vectors), numeral 37 designates an output vector set comprising a plurality of vectors read from the frame memory, numeral 26 designates an address counter which gives an address of the dynamic code book, and numeral 27 designates an index latch which latches an index corresponding to the address of the dynamic code book on detecting the minimum distortion.
FIGS. 14 and 15 are block diagrams illustrating constitution of an adaptive vector quantization encoder and decoder respectively. Numeral 5 designates a mean value separation normalizing circuit which separates the input vector into three components, i.e., the mean value, amplitude and normalized vector, numeral 25 designates a general-purpose code book, numeral 38 designates a block discrimination circuit which performs threshold value processing for conditional replenishment, numeral 39 designates a block information encoding circuit where block discrimination indices are encoded together per small block (n.sub.1 .times.n.sub.2, n.sub.1, n.sub.2 : integers) based on two-dimensional arrangement for example, numeral 40 designates a previous value predictive differential PCM encoding circuit, numeral 41 designates a block information decoding circuit which decodes the block discrimination index, numeral 42 designates a previous value predictive differential PCM decoding circuit, numeral 43 designates a mean value adding circuit, and numeral 44 designates an amplitude multiplying circuit.
In the apparatus in such constitution, since the portion from the A/D converter to the transmission buffer memory in the encoding section and the portion from the reception buffer memory to the D/A converter in the decoding section must operate in real time synchronized with video clocks, parallel processing concurrent with speed-up is accompanied by increase of the apparatus scale, and since the information inputted to the encoding control circuit is only the stored amount of the transmission buffer memory, control of the block discrimination threshold value following the movement is difficult. When the capacity of the frame memory within the encoding loop is only one picture field there is a problem that the transmission delay amount is increased in the case that the amount of information produced is so large that the input data of one picture frame cannot be all encoded.
Also in the apparatus of the prior art, even if all regions of the inputted picture are not required nor is a high resolving power needed, i.e., the large number of pixels is not required, all pixels must be encoded and transmitted in forms based on prescribed design, and, thereby, there is a problem that the information amount becomes large and therefore the time lapse is liable to occur, and it cannot be easily determined at what frame speed the transmitting side transmits to the other receiving side.
In the case of one encoder and one decoder, blocks within the picture are subjected to the vector quantization sequentially, and when the last block is quantized the encoding is finished, thereby during this process indices by the number of blocks are outputted as encoded data, and in the case of decoding, the blocks are received one after another, then subjected to vector quantization decoding one after another, and when the index of the last block is decoded the decoding is finished.
Consequently, in the case of application to transmission or retrieval of still pictures, even if necessary information is desired to be obtained in selection, the whole contents cannot be determined before the decoding reproduction of one picture field as a whole is completed, and there is a problem that a considerably long time is required for transmission or reproduction of recording, so that the selection cannot be performed immediately.
A contour holding filter in the prior art is shown in FIG. 16.
FIG. 16 is a block diagram illustrating a constitution example of a contour holding filter in the prior art. Numeral 45 designates a one-line delay element, numeral 46 designates a one-sample delay element, numeral 47 designates a multiplier, numeral 11 designates an adder, numeral 4 designates a subtractor, numeral 216 designates an aimed pixel sample as an object of smoothing, numerals 217, 218 designate pixel samples neighboring respectively at right and left sides on two-dimensional arrangement of picture frame, numerals 219, 220 designate pixel samples neighboring respectively at upper and lower sides on two-dimensional arrangement of picture frame, numeral 48 designates an absolute value operation unit, numeral 49 designates a comparator, numeral 50 designates a selector, numeral 221 designates a horizontal direction differential absolute value signal, numeral 222 designates a vertical direction differential absolute value signal, numeral 223 designates a horizontal direction filter output applied by smoothing in the horizontal direction, numeral 224 designates a vertical direction filter output applied by smoothing in the vertical direction, numeral 225 designates a horizontal and vertical filter output applied by smoothing in the horizontal and vertical directions, numeral 226 designates a selector indicating signal to control the selector output signal, and numeral 227 designates an output pixel sample where the aimed pixel sample is smoothed.
The contour holding filter in the prior art is constituted as above described and edge detection is performed according to the variation amount of the pixel value by peripheral pixels of the aimed pixel as an object of smoothing, but the effect of the filter and the variation amount do not always correspond to each other, and therefore there is a problem that, the error decision may cause deterioration of the picture quality.
An apparatus using an information producing amount control circuit to smooth the information producing amount is shown in FIG. 17.
FIG. 17 is a block diagram illustrating the constitution of an encoding section of an interframe adaptive vector quantization encoding apparatus. Numeral 1 designates an A/D conversion and block dividing circuit, numeral 51 designates a block discrimination circuit which outputs block discrimination information to perform conditional replenishment according to the mean value, variance and threshold value, numeral 7 designates a vector quantization encoder which performs vector quantization of the normalized vector and outputs a vector index, and performs DPCM on the mean value and the variance, and numeral 9 designates an information producing amount control circuit as an encoding control circuit which controls the threshold value used for block discrimination corresponding to the storage information amount of the transmission buffer.
Since the information producing amount control circuit of the picture encoding apparatus in the prior art is constituted as above described, previous encoding conditions are unclear and the encoding control in response to the movement amount of the picture cannot be performed, thereby the information producing amount with high accuracy is difficult, and when the movement amount is small, the threshold value is decreased excessively and the information producing amount becomes large for the beginning of the movement and there is a problem that the ability for detecting the beginning of the movement is deteriorated due to an increase in number of the time lapses.
A tree search vector quantizer in the prior art is shown in FIG. 18. FIG. 18 is a block diagram illustrating constitution of an n-stage tree search vector quantization encoder where pipeline processing is employed. In FIG. 18, numeral 207 designates an input vector, numeral 52 designates a first stage of an encoder where each stage is pipelined, numeral 53 designates a second stage of the encoder, numeral 54 designates an n-th stage of the encoder, numeral 301 designates an encoded output of the first stage of the encoder, numeral 302 designates an encoded output of the second stage of the encoder, numeral 303 designates an encoded output of the (n-1)th stage of the encoder, numeral 304 designates an encoded output of the n-th stage of the encoder, i.e., an output vector index, numeral 55 designates a latch which latches the index and outputs it at a definite timing, and numeral 210 designates an encoder output signal.
FIG. 19 is a block diagram illustrating a constitution example of the n-th stage of the encoder. In FIG. 19, numeral 56 designates a register which latches the input vector 207 in each stage, numeral 57 designates a code table which stores a pair of output vectors in the n-th stage of an output vector set having tree structure produced previously so that the output vector corresponding to the node point of each stage may become minimum distortion based on the distribution of input vectors, numerals 305 and 306 designate output vectors read from the code table 57, numeral 58 designates a distortion operation circuit which calculates distortion between the input vector 207 and the output vectors 305, 306, numeral 59 designates a comparator which compares two distortions as outputs of the distortion operation circuits, numeral 307 designates a signal indicating the comparison result in the comparator 59, and numeral 60 designates an index register which adds "0" or "1" to the encoded output 303 at the (n-1)th stage in accordance with the comparison result and outputs the encoded output at the n-th stage. Each stage of the encoder has a similar constitution. Differences are in the contents of the output vector code table of each stage, and in that the previous stage encoded output is not inputted to the first stage and that the input vector is not transmitted from the input vector register of the n-th stage (last stage) to next stage (shown by broken line in FIG. 18).
FIG. 20 is a block diagram illustrating a constitution example of a vector quantization decoder. In FIG. 20, numeral 61 designates a register which latches the index signal 304 inputted to the decoder, numeral 62 designates a code table which stores real output vectors corresponding to the last end node point of a search tree (equivalent to the contents of the code table at the last stage of the encoder), numeral 63 designates a register which latches an output vector read from the code table 62 in accordance with the index signal 304, and numeral 212 designates an output vector.
Since the tree search vector quantizer in the prior art is constituted as above described, in the encoder, there is a problem that an output vector code table memory capacity of about twice the number of real output vectors is required. For example, when the number of output vectors is equal to N (=2.sup.n), output vectors of (2.sup.n+1 -2) in number must be stored in the encoder and output vectors of 2.sup.n in number must be stored in the decoder.
When a motion picture and a still picture are transmitted, constitution of a video encoding transmission apparatus in the prior art is shown in FIG. 53. In FIG. 53, numeral 826 designates a motion picture camera, numeral 827 designates a motion video signal being output from the motion picture camera 826, numeral 828 designates a motion picture encoding and decoding apparatus (hereinafter referred to as "codec") which encodes the motion video signal 827 and decodes motion picture encoded data 829 into motion video signal 832, numeral 829 designates motion picture encoding data, numeral 830 designates a transmission control section which connects a motion picture codec 828 or a still picture codec 836 to the opposite station, numeral 831 designates multiplexing data transmitted or received by the transmission control section 830, numeral 832 designates a motion video signal decoded by the motion picture codec 828, numeral 833 designates a monitor which displays a picture of the motion video signal, numeral 834 designates a still picture camera, numeral 835 designates a still video signal, numeral 836 designates a still picture codec which performs encoding and decoding of a still picture, numeral 837 designates still picture encoded data, numeral 838 designates a still picture video signal, and numeral 839 designates a monitor which displays the still picture represented by video signal 838.
FIG. 54 is a block diagram illustrating an example of a motion picture encoding section of a picture encoding transmission apparatus in the prior art. Numeral 801 designates an input signal obtained by digitizing the camera signal, numeral 802 designates a blocking circuit which blocks a signal scanned in the raster direction and outputs it, numeral 804 designates input signal series being blocked into units of encoding, numeral 805 designates a dynamic vector quantizer, numeral 806 designates a DVQ index, numeral 807 designates a DVQ output vector, numeral 825 designates a filter for eliminating noise from the vector signal, numeral 809 designates a DVQ output vector passing through the filter, numeral 810 designates a subtractor, numeral 811 designates an interframe differential vector, numeral 812 designates an adaptive vector quantizer, numeral 813 designates an adaptive vector quantization (hereinafter referred to as "AVQ'") encoding information, numeral 814 designates an AVQ output vector, numeral 815 designates an adder, numeral 816 designates a locally decoded vector, numeral 817 designates a field memory for storing the number of pixels in one field of the motion picture, and numeral 818 designates a previous frame vector.
FIG. 55 is a block diagram illustrating an example of a decoding section of a picture encoding transmission apparatus in the prior art. Numeral 806 designates a DVQ index, numeral 820 designates a dynamic vector quantizer decoding section, numeral 825 designates a digital filter, numeral 809 designates a DVQ output vector passing through the filter, numeral 813 designates AVQ encoding information, numeral 819 designates an adaptive vector quantizer decoding section, numeral 814 designates an interframe differential vector locally decoded, numeral 815 designates an adder, numeral 816 designates a locally decoded vector, numeral 817 designates field memory for storing the number pixels of the motion picture, numeral 823 designates a deblocking circuit which performs scan conversion of signal series blocks into the raster configuration and numeral 824 designates a motion picture output signal series.
Next, the operation will be described. In FIG. 53, an image is converted into an electric signal by the motion picture camera 826 and a motion picture signal 827 can be obtained. The motion picture signal 827 is compressed and encoded in the motion picture codec 828 and transmitted as motion picture encoded data 829 to the transmission control section 830. The transmission control section 830 multiplexes the motion picture encoded data 829 together with other data to be transmitted and transmits the multiplexed data 831, and also receives multiplexed data transmitted, at the same time, from the opposite station and performs distribution. If the motion picture encoded data 829 is obtained from the received multiplexed data 831, it is transmitted to the motion picture codec 828 and the motion picture signal 832 from the opposite station is decoded and displayed on the motion picture monitor 833.
On the other hand, the still picture codec 836 performs encoding operations only for transmission of the a still picture to an opposite station. Codec 836 encodes the still picture signal 835 from the still picture camera 834, and the signal is transmitted as still picture encoded data 837 to the transmission control section 830. In general, in the still picture encoding, since the number of samples is greater than that of the motion picture and encoding utilizing correlation between continuous frames cannot be performed as in the case of the amount of motion picture, the still picture encoded data of one picture frame is considerably greater than the amount of motion picture encoded data of one picture frame. Consequently, if the still picture transmission is started, the transmission control section temporarily stops the transmission/reception of the motion picture encoded data so that the still picture transmission can be completed in shortest period.
In a block diagram of a motion picture codec encoding section of FIG. 54, the input signal series 801 is inputted from the camera and digitized, and then blocked into blocks of m by n pixels as quantized units in a blocking circuit 802 and becomes an input vector 804.
In the dynamic vector quantizer 805, the input vector 804 is compared with a dynamic code table comprising a previous frame signal 818 or the like read from the field memory 817, and quantized into the previous frame vector at displaced position about the position within the picture frame of the input vector 804, thereby the DVQ index 806 and the DVQ output vector 807 corresponding to the displacement amount can be obtained. The DVQ output vector 807 is smoothed in a digital filter 825 so as to prevent the quantization noise from piling up.
The DVQ output vector 809 smoothed in the filter enters a subtractor 810 and is subtracted from the input vector 804, thereby the interframe differential vector 811 can be obtained. The interframe differential vector 811 is subjected to adaptive processing such as movement detection, mean value separation normalizing or the like in an adaptive vector quantizer 812, thereby an AVQ output vector 814 and AVQ encoded information 813 such as an index are outputted. The AVQ output vector is added in an adder 815 to the DVQ output vector 809 smoothed in the filter, and becomes a locally decoded vector 816 and is written in corresponding position of a field memory 817.
Contents of the field memory 817 are quoted in the DVQ on encoding the next frame. The AVQ encoded information 813 and the DVQ index are subjected to variable word length encoding and transmitted as transmission data by the transmission control section, but in order to make the amount of transmission information constant, if the amount of the generated information is large, the frame as an object of encoding is thinned out and the time-lapse control is performed.
In a block diagram of a decoding section of FIG. 55, the DVQ index 806 and the AVQ encoded information 813 are decoded into moving video signal series 824. The DVQ index 806 enters a DVQ decoding section 820 and a digital filter 825, and the previous frame vector at the displaced position according to the DVQ index 806 is read from the corresponding position of the previous decoded picture within the field memory 817 and smoothed in the digital filter 825. On the other hand, the AVQ encoded information 813 is decoded by the AVQ decoding section 819 into an interframe differential locally decoded vector 814, and added in an adder 815 to the previous frame vector 809 smoothed in the filter, thereby a locally decoded vector 816 can be obtained. The locally decoded vector 816 is written in the corresponding position of the field memory 817 for decoding the next frame.
Operation of the motion picture codec has been described, and the motion picture codec decreases the number of pixels so as to encode a motion picture under a restricted amount of information. On the contrary, since the high resolving power is required for encoding the still picture or painting and calligraphic works, it is difficult to perform encoding of the motion picture and encoding of the still picture using the same number of pixels. Consequently, in order to transmit the motion picture and a still picture, the still picture codec independent of the motion picture codec must be utilized.
Since the picture encoding transmission apparatus in the prior art is constituted as above described, the motion picture codec and the still picture codec must be provided independently, thereby the cost becomes high. When one encoding section is used commonly for both codecs, for the motion picture, the number of pixels is too large and the amount of generated information becomes too large, to reproduce the movement smoothly via the ordinary lines, or for the still picture, the resolving power is not sufficient and the performance cannot be satisfied. This is also a problem.